Volume XVI 



Number 6 



THE 



Journal of Geology 



A Semi -Quarterly flagazine of Geology and 

 Related Sciences 



SEPTEMBER-OCTOBER, igo8 



EDITORS 



T. C. CHAMBERLIN, in General Charge 



R. D. SALISBURY R. A. F. PENROSE, Jr. 



Geographic Geology Economic Geology 



J. P. IDDINGS C. R. VAN HISE 



Petrology Structural Geology 



STUART WELLER W. H. HOLMES 



Paleonto logic Geology Anthropic Geology 



S. W. WILLISTON, Vertebrate Paleontology 



ASSOCIATE EDITORS 



SIR ARCHIBALD GEIKIE 



threat Britain 

 H. ROSENBUSCH 



Germany 

 CHARLES BARROIS 



France 

 ALBRECHT PENCK 



Germany 

 HANS REUSCH 



Norway 

 GERARD DE GEER 



Sweden 



G. K. GILBERT 



Washington, D. C. 

 H. S. WILLIAMS 



Cornell University 

 C. D. WALCOTT 



Smithsonian Institution 

 J. C. BRANNER 



Stan/ora University 

 W. B. CLARK 



Johns Hopkins University 

 O. A. DERBY 



Brazil 



T. W. E. DAVID, Australia 



Ef)e ^anibersitg of €i[)icago ^^ress 



CHICAGO AND NEW YORK 

 William Wesley & Son London 



